Worldwide, hemorrhagic shock in major trauma remains a major potentially preventable cause of death. Controlling bleeding and subsequent coagulopathy is a big challenge. Immediate assessment of unidentified bleeding sources is essential in blunt trauma patients with hemorrhagic shock. Chest/pelvic X-ray in conjunction with ultrasonography have been established classically as initial diagnostic imaging modalities to identify the major sources of internal bleeding including intra-thoracic, intra-abdominal, or retroperitoneal hemorrhage related to pelvic fracture. Massive soft tissue injury, regardless of whether isolated or associated with multiple injuries, occasionally causes extensive hemorrhage and acute traumatic coagulopathy. Specific types of injuries, including soft tissue injury or retroperitoneal hemorrhage unrelated to pelvic fracture, can potentially be overlooked or be considered “occult” causes of bleeding because classical diagnostic imaging often cannot exclude such injuries. The purpose of this narrative review article is to describe “occult” or unusual sources of bleeding associated with blunt trauma.

In recent years, it has become evident that molecular hydrogen is a particularyl effective treatment for various disease models such as ischemia-reperfusion injury; as a result, research on hydrogen has progressed rapidly. Hydrogen has been shown to be effective not only through intake as a gas, but also as a liquid medication taken orally, intravenously, or locally. Hydrogenʼs effectiveness is thus multifaceted. Herein we review the recent research on hydrogen-rich water, and we examine the possibilities for its clinical application. Now that hydrogen is in the limelight as a gaseous signaling molecule due to its potential ability to inhibit oxidative stress signaling, new research developments are highly anticipated.